Group B streptococcal infection

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Last reviewed: 26 Aug 2022

Last updated: 07 May 2020

Most common cause of early, severe infection in newborns.

Also a cause of infection in pregnancy, people with diabetes, immunocompromised people, and older adults.

Presentation depends on the age of the patient and the underlying risk factor.

Diagnosis is confirmed by isolation of group B streptococci (GBS) from usually sterile body fluid.

Targeted antibiotic therapy is the mainstay of therapy in patients with demonstrated GBS infection.

Incidence and mortality are highest in older people.

Definition

Group B streptococci (GBS), also known as Streptococcus agalactiae, are gram-positive bacteria that normally colonize the gastrointestinal tract, perineum, and vagina. They can cause invasive infections at any age, but infections are most common in the neonatal period, in older people, and in adults with predisposing factors (i.e., pregnancy, diabetes, immunocompromised). GBS can cause a range of infections including sepsis, cellulitis, pneumonia, and meningitis. This monograph deals with confirmed group B streptococcal infection only.

History and exam

Key diagnostic factors

fever
symptoms of meningitis
signs of meningitis
symptoms of sepsis
signs of sepsis
symptoms of pneumonia
signs of pneumonia
symptoms of UTI
signs of UTI
symptoms of cellulitis
signs of cellulitis
symptoms of septic arthritis
signs of septic arthritis
symptoms of conjunctivitis
symptoms of sinusitis
signs of sinusitis
symptoms of otitis media
signs of otitis media
symptoms of endometritis
signs of endometritis
signs of chorioamnionitis

More key diagnostic factors

Other diagnostic factors

nonspecific signs of infection in neonate
nonspecific signs of infection in older patients
symptoms of intra-abdominal infection
signs of intra-abdominal infection
midgestation abortion or preterm labor

Other diagnostic factors

Risk factors

0 to 7 days of age
maternal fever during labor
premature rupture of membranes (PROM)
previous baby with GBS disease
maternal GBS colonization
GBS bacteriuria during pregnancy
preterm delivery (<37 weeks)
low birth weight (<2500 g)
deficient maternal-specific IgG at term
twin sibling with GBS disease
maternal age <20 years
chorioamnionitis
age >60 years
pregnancy
diabetes mellitus
advanced hepatic disease
advanced renal disease
presence of central venous catheter
urologic disorders
break in skin integrity or skin ulcers
neurologic disease
immunosuppression
nursing-home resident
black or Hispanic race
malignancy
primiparity
obstetric manipulation
presence of urinary catheter
HIV infection
trauma
asthma
consumption of placenta capsules

More risk factors

Diagnostic investigations

1st investigations to order

CBC
BUN
serum electrolytes
serum glucose
coagulation studies
LFTs
C-reactive protein (CRP)
blood culture
cerebrospinal fluid (CSF) Gram stain
CSF culture
CSF cell count and differential
CSF glucose and protein
antigen detection in CSF
Gram stain and culture of other sterile body fluids
chest x-ray
joint x-ray
CT head

More 1st investigations to order

Investigations to consider

echocardiography

More investigations to consider

Treatment algorithm

ACUTE

early- or late-onset neonatal infection (0-89 days of age)

infants and children

adults

Contributors

Authors

Brendan Healy, MBChB, BSc (Hons), MRCP, FRCPath

Consultant in Microbiology and Infectious Diseases

University Hospital of Wales

Cardiff

Disclosures

BH has received educational grants and fees for consultancy from a number of pharmaceutical companies, including BMS, Gilead, Jannsenn, Abbvie, ViiV, and MSD. This is principally in work relating to hepatitis C and HIV. BH has carried out consultancy work on some antibiotics, including fidaxomicin, linezolid, tedizolid, ceftobiprole, and ceftaroline. BH declares he has no competing interests in relation to the work carried out for this topic review, Group B streptococcus.

Acknowledgements

Dr Brendan Healy would like to gratefully acknowledge Dr Susannah Froude and Dr Harriet Hughes, previous contributors to this topic.

Disclosures

SF declares that she has no competing interests. HH declares that she has received funds from Gilead and Biocomposites related to conference registration, travel, accommodation, and speaker fees.

Peer reviewers

William A. Petri, Jr, MD, PhD, FACP

Chief and Professor of Medicine

Division of Infectious Diseases and International Health

University of Virginia Health System

Charlottesville

Disclosures

WAP declares that he has no competing interests.

James R. Hanley, MD, FAAP

Assistant Professor

Pediatrics

Attending Physician

Pediatric Emergency Medicine

University of Southern Alabama Children's and Women's Hospital

Mobile

Disclosures

JRH declares that he has no competing interests.

Differentials
- Sepsis caused by other organisms
- Endocarditis caused by other organisms
- Neonatal CMV infection
More Differentials
Guidelines
- Prevention of early-onset group B streptococcal disease in newborns
- The prevention of early-onset neonatal group B streptococcal disease
More Guidelines
Patient leaflets
Cellulitis and erysipelas
Conjunctivitis
More Patient leaflets
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Group B streptococcal infection

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

early- or late-onset neonatal infection (0-89 days of age)

infants and children

adults

Contributors

Authors

Brendan Healy, MBChB, BSc (Hons), MRCP, FRCPath

Disclosures

Acknowledgements

Disclosures

Peer reviewers

William A. Petri, Jr, MD, PhD, FACP

Disclosures

James R. Hanley, MD, FAAP

Disclosures

Differentials

Guidelines

Patient leaflets

Log in or subscribe to access all of BMJ Best Practice

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